This can be done by dividing the natural log of 2 by the half-life of potassium-40. The half-life of potassium-40 is given as $1.3 \times 10^{9}$ years. So, the decay constant is given by:
\[k = \frac{\ln(2)}{t_{1/2}} = \frac{\ln(2)}{1.3 \times 10^{9} \,
Show more…